1. Field of the Invention
This invention relates generally to interfacing electrical components, and, more particularly, to a method and apparatus for automatically selecting an appropriate voltage level for an interface signal.
2. Description of the Related Art
The field of electronics in general, and personal computers in particular, is evolving at a very fast pace. As semiconductor devices have become smaller and more densely populated, voltage and power requirements have fallen dramatically. For example, the operating voltage of some semiconductor devices, such as microprocessors, has recently fallen from about 3.3V to about 2.5V. Semiconductor devices that interface with and support microprocessors have historically been designed to operate at similar voltages, or at least be designed to receive and deliver signals at these voltages. Typically, these supporting semiconductor devices are located on a motherboard along with the microprocessor. To facilitate upgrades, the motherboard has been designed with sockets that allow for the removal and replacement of the microprocessor, as faster and more powerful microprocessors become available. However, where the next generation of microprocessor uses a substantially reduced operating voltage, then the motherboard and/or supporting semiconductor devices may not operate properly, impeding the ability to upgrade.
This impedance to upgrading is problematic for at least three reasons. First, consumers may be reluctant to purchase personal computers that cannot be readily upgraded as better technology becomes available. Second, manufactures of supporting semiconductor devices may be forced to redesign with each new microprocessor. Third, manufacturers of personal computers may be forced to substantially redesign their motherboards each time a new microprocessor is introduced. This significant redesign effort is inefficient and costly.
Alternatively, motherboard manufacturers may be able to design in some flexibility through the use of manually selectable jumpers. Manually selectable jumpers are problematic in that they leave open the possibility that improper installation will occur at the time that the upgrade is attempted. Mislocated jumpers will, at best, cause poor performance or inoperability, and may even damage the personal computer.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.